Some display devices create an image by scanning a beam of varying intensity across a display surface. For example, some projection display devices scan a light beam across a surface in a row and column pattern. The rate at which the light beam scans is typically not related to the rate at which display data is supplied to the projection display device.
Some projection display devices include frame buffers in the form of solid state memory to store data to be displayed. The frame buffer allows storage of display data arriving at various rates to be retrieved at different rates as dictated by the scanning rate of the projection display device. Although frame buffers provide a necessary function in some display devices, they can consume significant resources on integrated circuits. For example, a VGA (640×480) display with 24 bits per pixel uses 640×480×24=over seven million bits of storage. Resources consumed by frame buffers increase as the display resolution increases.